1. Field of the Invention
The present invention relates to an electronic device including a capacitor element and a manufacturing method thereof, and in particular, an electronic device including a capacitor element in which a high dielectric constant film and a ferroelectric film are used for a capacitor dielectric film.
2. Description of the Related Art
Recently, a capacitor element used for an electronic device represented by a semiconductor device has been used for various purposes in a field of the electronic devices, as a decoupling capacitor suppressing a voltage noise and a voltage variation generated by a coupling between power bus lines, a storage capacitor of a semiconductor memory device such as a DRAM and FeRAM, an active variable element used for a microwave element, and so on.
As a capacitor film material of the capacitor element, materials with high dielectric constant, ferroelectric constant having a perovskite structure (composition formula: ABO3) containing at least Sr and O, such as, for example, SrTiO3 (strontium titanium oxide) (STO), (Ba (barium), Sr (strontium)) TiO3 (titanium oxide) (BST) are attracting attention, as shown in Patent Documents 1, 2.
[Patent Document 1] Japanese Patent Application Laid-open No. Hei 8-227980
[Patent Document 2] Japanese Patent Application Laid-open No. 2000-58792
In the electronic device including the capacitor element having a capacitor film composed of the dielectric material having the above-stated perovskite structure, improvements of various characteristics such as a large capacity, low leak current, and longer operating time are required.
However, an alignment direction of a film has a strong relation with the characteristics in the dielectric film having the perovskite structure. Accordingly, when the alignment direction of the film is selected to optimize a certain characteristic (for example, a voltage variability of a capacity value), it is inevitable to give up the other characteristics (for example, a leak current characteristic).
Besides, it is necessary to improve the characteristics of the capacitor element from other aspects to realize further improvement of device characteristics, even when the optimization of the capacitor element is performed while specializing in a certain application. Accordingly, a structure capable of improving various characteristics simultaneously in each aspect has been desired.